Knowledge and conservation of the marine and estuarine fishes (Chondrichthyes and Teleostei) of the north coast of Brazil

The tropical western South Atlantic, which includes a substantial portion of the Brazilian Exclusive Economic Zone, is a region of endemism broadly recognized as being of prime importance for the conservation of the marine biodiversity. The north coast of Brazil, which comprises the states of Amapa, Para and Maranhao from the mouth of the rio Oiapoque to the mouth of the rio Parnaiba, harbors the largest continuous mangrove in the world, with approximately 8,900 km(2). The high discharge of freshwater and continental sediments in the delta of the Amazonas affects the regime of tides, ocean currents, and several oceanographic processes of the north coast, with direct impact on the composition of the biota found in the region. Despite its economic value and intrinsic biological relevance, several aspects of the diversity of the marine and estuarine fishes of the region are poorly known. This situation results mainly from a historical imbalance in terms of the number of studies devoted to increasing the knowledge of the marine biota along the Brazilian coast, such as those dealing with species inventory and taxonomic revisions, which are typically concentrated in the south and southwestern portions of the country. The scientific production focused on marine organisms of the north coast is also imbalanced, and reflects the relatively small number of taxonomists and research groups working on that subject. The insufficient knowledge of the biodiversity of the marine and estuarine fishes of the north coast is an impediment to the implementation of adequate public policies aimed at the management of natural resources in the region. In the long term, that situation is potentially harmful in terms of conservation of a still poorly known biota. A better understanding of the marine fish fauna of the north coast of Brazil will be achieved only through the investment in scientific research and personnel training in systematics and biogeography, coupled with the modernization of the current infrastructure and expansion of scientific collections of the region.